Heart failure remains a major concern in developed countries. About 5.7 million people in the U.S. have heart failure, and it results in about 3000,000 deaths each year. One treatment option for patients with symptomatic heart failure (HF) resulting from systolic dysfunction is cardiac resynchronization therapy (CRT). CRT is achieved by simultaneously pacing both the left and right ventricles in a synchronized manner. Numerous clinical investigations have demonstrated that CRT may improve clinical status, functional capacity, and survival in select patients with ventricular dyssynchrony.
Despite the success of cardiac resynchronization therapy shown in several international, multicenter, placebo controlled clinical trials, one out of three patients undergoing CRT will not positively respond to the therapy. Two potential reasons for a patient's non-response to CRT are: 1) poor selection criteria or 2) non-optimal implementation/application of the biventricular pacing device. A significant amount of work has been done to use imaging to address selection of candidates for CRT. However, much less has been done to optimize device performance by selecting and planning lead positions on the myocardium. To achieve the highest physiological and mechanical efficiency and maximize the benefit of CRT, one would like to place the left ventricular (LV) pacing lead at the location of the most delayed contraction that is not predominately scar tissue. Retrospective studies have shown that if the LV lead is located at the “most dyssynchronous” or “latest contracting” region, response rates are improved.